Early stage crystallization kinetics in metallic glass-forming alloys

•Heterogeneous nucleation may precede the homogeneous one in an alloy.•High kinetic constants and the nucleation rate at the initial stage.•Metallic glasses have heterogeneous nucleation sites which saturate later.

The crystallization kinetics and structural changes of a few metallic glassy alloys were monitored using X-ray diffraction, transmission electron microscopy, differential scanning and isothermal calorimetry methods. Microstructural observations were used to estimate the nucleation and growth rates. A clear comparison of the differences in the crystallization kinetics in the metallic glassy samples is observed at the early and later crystallization stages.